This is a write-up for Clisay challenge from NahamCon CTF.
Let’s download the file to see what we can do with it. Open up the terminal, then check the file type with the file command.
It’s just an executable file and if we run ls -la on the terminal to see the permissions of the file, we would see that it’s not executable. So, let’s give it the executable permission bit and try to run it.
chmod +x clisay
Now it’s executable, let’s run it.
It just outputs some strings. let’s see if it contains any interesting printable characters with the strings command tool.
Done, We can easily notice the flag. It is splited into two halfs. We can use grep to extract its halfs then rejoin them again.
If you don’t like to copy and paste the two halfs XD, You can simply run the below line on the terminal.
flag{Y0u_c4n_r3Ad_M1nd5}